Yesterday, the Spanish newspaper El Pais released a report of a meeting President Bush held in February 2003 with the Spanish prime minister, Jose Maria Aznar, who joined Tony Blair in providing western European backing for the invasion of Iraq that March. The report revealed that Bush had received indications that Saddam Hussein would be willing to accept exile in order to avoid war. There was, of course, a catch: Saddam wanted to be allowed to take $1bn and some information relating to WMD programmes out of the country with him.

Bush did not, however, reject the offer because the price was too high. Even his own gross undercount of the likely cost of war had him anticipating $50bn or more in expenditures.

The option, however, wasn't seriously explored. Instead, Bush just said there could be "no guarantee" for Saddam, thus essentially foreclosing any chance of a diplomatic resolution. That Bush was more or less hell-bent upon war has been a widely-aired view for some time - but the reasons behind his decision have received far less scrutiny. The crux of the matter, however, is that the Iraq war was not just about Iraq, but about a new approach to nuclear proliferation more generally. The old way had been based on binding international commitments that, while allowing the US and a select few other countries to possess nuclear weapons, did impose some real commitments on the nuclear weapons states. Bush and his team, viewing international agreements as like strings used by the world's Lilliputians to tie down the American Gulliver, wanted another way.

That way, known as "counterproliferation" by its advocates, was, in essence, brute force. The US would break its non-proliferation treaty commitments by building a new generation of "bunker buster" nukes, turn a blind eye to nuclear activities by friendly states, and restrain WMD acquisition by hostile states through intimidation rather than a legitimate international process. Iraq was targeted not merely on its own terms but in order that Bush might make an example out of Saddam and send a message to the leaders of Iran, Syria, North Korea and other states. Cutting a deal with Saddam wasn't an option.

Unfortunately, as a result of the same thinking, neither were any number of other moves that could have improved American policy. In particular, the invasion force needed to be small enough, and the reconstruction plan fast and cheap enough, that the US could credibly threaten to do it again if other countries didn't get the message.

Iraq's neighbours, meanwhile, couldn't very well be intimidated by being given a seat at the table in the management of Iraq's future. Instead, the invasion and occupation had to be carried out in a way that was maximally threatening to Syria and Iran. But, of course, this all backfired - the plan for post-war Iraq proved inadequate, nobody was intimidated by the resulting mess, and Syria and Iran were put in a position of having every incentive to help stir the pot of instability in Iraq in order to keep the pressure off of them.

These problems were not, however, the results of bungling or incompetence but - like the refusal to seriously entertain cheaper and easier ways of getting Saddam out of power - necessary consequences of the underlying ideological vision that motivated the war.